Thrombospondin-2 is essential for myocardial matrix integrity: increased expression identifies failure-prone cardiac...

Area of Science:

• Cardiology
• Molecular Biology
• Genetics

Background:

• Cardiac hypertrophy is a precursor to heart failure (HF), but predicting HF progression remains challenging.
• Identifying early molecular markers can enable timely intervention for hypertrophied myocardium at risk of failure.

Purpose of the Study:

• To identify specific genes expressed during compensated hypertrophy that predict subsequent progression to heart failure.
• To investigate the role of thrombospondin-2 (TSP2) as a potential early molecular predictor of HF.

Main Methods:

• Microarray analysis of hearts from renin-overexpressing rats that progressed to HF versus those that remained compensated.
• Analysis of cardiac biopsy specimens from rats during compensated hypertrophy to monitor subsequent HF development.
• Assessment of TSP2 expression in human hypertrophied hearts and its correlation with ejection fraction.
• Evaluation of TSP2 knockout mice subjected to angiotensin II to assess cardiac rupture and failure, and matrix metalloproteinase (MMP) activity.

Main Results:

• TSP2 was selectively overexpressed in biopsy specimens from rats that later progressed to HF.
• TSP2 expression was increased in human hypertrophied hearts with reduced ejection fraction.
• TSP2 knockout mice exhibited increased susceptibility to fatal cardiac rupture and failure upon angiotensin II administration, with elevated MMP-2 and MMP-9 activity.
• Wild-type mice did not show these severe outcomes.

Conclusions:

• TSP2 is a crucial regulator of cardiac matrix integrity, essential for myocardium adaptation to increased load.
• TSP2 may regulate matrix metalloproteinase (MMP) activity, influencing cardiac remodeling.
• TSP2 expression serves as an early molecular signature in hypertrophied hearts predisposed to failure, offering a potential predictive biomarker for HF.